G.R.O.S.S. is an anti-girl club, as popularized by Calvin & Hobbes. The name is an acronym that stands for Get Rid Of Slimy GirlS

Based in a treehouse (with occasional emergency meetings inside a cardboard box), the main objective of G.R.O.S.S. club is to annoy, bother, and harass girls. Calvin and Hobbes are its only members, and they sometimes plan missions to do so.

Look for local chapters of G.R.O.S.S. now forming in a neighbourhood near you.